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Just one contract left un-traced could start new line of Ebola transmission

Earlier this summer, Kelsey Mirkovic, a disease detective with the Centers for Disease Control and Prevention, entered a hut with her team in Gueckedou, Guinea, to speak with a man who had Ebola.

Their mission: to get the names of everyone he'd had contact with while he was ill, so that they could stop those people from spreading the disease.

"Who lives with you here? Who has eaten off the same plate as you? Who has bathed you and taken care of you?" they asked him.

Just his wife, the man answered.

Mirkovic and her team knew that wasn't true.

They knew he had children, and they knew that in West Africa, families and even neighbors eat off the same plate and bathe and care for sick people. They explained to the man how important it was to stop Ebola, and that his friends and family would be treated with respect.

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Their pleas didn't work.

Mirkovic saw this scene play out over and over again. One of her colleagues at the CDC who's worked in Liberia says preliminary data shows they could be missing 40 to 60% of the contacts of known Ebola patients.

"This is one of the hardest parts of the response," said Dr. Brett Petersen, a medical officer with the CDC.

Mirkovic agrees. She says she understands why Ebola patients don't want to name names: There was a rumor going around the communities she worked in that getting on a contact list meant you would die -- and the deaths would happen in the same order as they appeared on the list.

"I understand they're scared," she said. "But it's very frustrating."

The Ebola outbreak in the West African nations of Guinea, Sierra Leone, Liberia and Nigeria has killed nearly 1,500 people. Just one contact left un-traced could go on to start a whole new line of Ebola transmission.

"It's like fighting a forest fire. If you leave behind even one burning ember, one case undetected, it could reignite the epidemic," Dr. Thomas Frieden, the director of the CDC, told reporters at a press conference earlier this summer.

"Contact tracing is a formidable challenge," said Dr. Margaret Chan, director-general of the World Health Organization. "In some areas, chains of transmission have moved underground. They are invisible. They are not being reported."

There's no solid number of how many contacts have gone missing. Petersen said the CDC arrived at the 40 to 60% number because in some communities, each sick person has only listed an average of two contacts -- and households commonly have five or six people.

Mirkovic, an officer with the CDC's epidemic intelligence service, said when she and her team felt patients weren't being honest, they would try to get information from neighbors or community leaders.